Simple Variables Predict Need for Massive Transfusion

Action Points

Explain to interested patients that three simple, readily available variables can identify trauma patients who are likely to require massive transfusion.

Note that the findings came from a retrospective review of medical records, not a randomized, controlled clinical trial.

PORTLAND, Ore., Oct. 29 -- The need for massive transfusions to prevent exsanguination can be quickly identified in trauma patients by three simple clinical variables, investigators here have found.

The combination of a hemoglobin value of 11 g/dL or less, an international normalized ratio (INR) of more than 1.5, and a penetrating mechanism of injury reliably predicted the need for massive transfusion, Martin Schreiber, M.D., of Oregon Health and Science University, and colleagues, reported in the October issue of the Journal of the American College of Surgeons.

Hemoglobin of 11 g/dL or less was the single most predictive variable, resulting in an odds ratio of 7.7.

"Using rapid laboratory technology, these variables are available within a few minutes of the patients' arrival, allowing the treating physicians to organize the resources necessary," the authors concluded.

Although the findings were based on an evaluation of military combat injuries, they are readily applicable to any trauma center, said Dr. Schreiber.

Hemorrhage is the leading cause of death on the battlefield, and prevention of exsanguination depends on rapid control of bleeding and transfer to definitive care. The most severely injured patients require massive transfusion to restore adequate oxygen delivery, the authors noted.

Because of the intensive resources required, the logistics involved in obtaining adequate blood products, and the demand for timeliness, early identification of patients who will require massive transfusion is essential, the authors said. However, a paucity of information exists about predictors of massive transfusion in trauma patients.

Dr. Schreiber and colleagues hypothesized that the INR and a penetrating mechanism of injury would predict the need for massive transfusion, defined as 10 or more units of a combination of stored red blood cells and fresh whole blood within the first 24 hours after injury.

To test their hypothesis they retrospectively reviewed data on 558 patients treated at two combat support hospitals in Iraq. The study population consisted of 546 (96.8%) men, and 467 (84%) had penetrating injuries.

The investigators found that 247 (44.3%) of the patients required massive transfusion, compared with 311 who did not. Patients requiring massive transfusion had an international severity score of 22 compared with 5 for patients who did not require massive transfusion (P<0.001). Survival to discharge from the combat support hospital was 61% in patients requiring massive transfusion versus 99% (P<0.001).

Eight potential predictors of massive transfusion were examined by univariate analysis: age, sex, prothrombin time, partial thromboplastin time, INR, hemoglobin, platelet count, and blunt (versus penetrating) mechanism of trauma. Six of the factors (all but age and sex) were predictive in the univariate analysis, but only three (Hbâ‰¤11, INR>1.5, and penetrating injury) remained predictive after logistic regression analysis (odds ratio 2.6 to 7.7).

Noting previous evidence of an association between coagulopathy, massive transfusion, and mortality, the authors concluded that "the correlation. . .underscores the importance of designing the resuscitation to replace coagulation factors and restoring perfusion."

The authors noted several limitations of the study. "It is a retrospective analysis limited by the data that were available in a combat setting. Physiologic data were not available on all patients and laboratory analyses were limited."

"Data on patients undergoing massive transfusion were collected at one hospital, and data on all patients were collected at the second hospital. Patients at the second hospital who did not receive massive transfusion served as controls for the massive transfusion population at both hospitals. Although they were not detected, differences in practice between the two hospitals might have affected the results."

No financial disclosure information was reported.

Reviewed by Zalman S. Agus, MD Emeritus Professor at the University of Pennsylvania School of Medicine